What Is Red Tide? Florida Beaches Clogged With Thousands Of Dead Fish During Algae Bloom

Bioluminescent phytoplankton create their own light during a red tide in the rolling surf along the coast of Leucadia, California, Sept. 29, 2011. Photo: Reuters

The Florida Fish and Wildlife Conservation Commission announced in a Tuesday news release that it had discovered "naturally occurring" red tide algae blooms in three counties near the state's west coast. And although red tide occurs annually in the Gulf of Mexico, reports indicate it's already begun to kill thousands of fish and drive away beach tourists.

"We come out here, the fish are dead and it stinks like heck," an unidentified visitor on Anna Maria Island told FOX 13. "I can't take that smell."

Florida's red tide is caused by Karenia brevis, a microorganism that in large concentrations make toxins that poison shellfish and make the air hard to breathe, according to the National Ocean Service. The color is -- you guessed it -- red.

Beachgoers with respiratory issues or sensitive noses may be affected. But the true losers of red tide are the fish -- thousands of grouper, pinfish, sea trout and snook have washed up dead on the shores so far, WTSP reported. The fish kills have been concentrated in Pinellas, Manatee and Sarasota counties, according to the wildlife commission.

For humans, the main risk associated with red tide is breathing in toxins that can cause throat and eye problems. People also need to watch after their dogs, taking care to clean them after they've been in the ocean, the Bradenton Herald reported.